Gapping higher
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Gapping Smaller
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Discuss.
M3 Sedan Club President #21
larger gap = more power, better combustion.
larger gap = easier to blow out with FI
smaller gap = less power, reliable spark
smaller gap = harder to blow out at high psi
key is to gap plugs as wide as possible before you get spark blow out.
1005whp/831wtq little bit of low boost pump gas magic...
Im assuming bigger gap = better gas mileage as well yes?
M3 Sedan Club President #21
So where is everyone gapping @ I'm @ .025 with A 7 heat range from NGK
I am also at .025 with the 7 bpr7es ngk
spark blows out at just 8psi around 4500rpm if you forget to gap them down to .025 haha
I didnt notice a change in milage when I swapped plugs and gaps... I have a msd blaster coil that I think ignites my mix pretty well either way.
My car was missing at .025" at 18psi with Bkr7e's
I switched to R5671A-8's gapped to .022" and they have been working great so far (about 75 miles)
According the NGK's website if your plug tip is white then your plug is running to hot.
-Kyle 1995 Custom Turbo M3 SOLD!
Funny this thread is today. I am good to 17psi at .027 gap on a 9 heat range plug.
When I try to boost past 17psi I blow out spark.
I have gapped down to .022-.018 and have had the same results.
In my bag I have a friends plasma coils and a set of 8 heat range plugs.
I am going to start at .035 and gap down to .020 to hit 25psi.
Btw, I am running 110 octane at 19 degrees total timing.
TEC-3R, T4 GT40, WISECO, EAGLE, SUPERTECH, O-RING'D "FRANKENSTEIN" STROKER.
996WHP 2.8 and going nowhere fast
. e36 4Dr with A/C and leather seats in U.S.
www.bmwturbo328.com 9.93@152.6
Great topic. I think mine are at .028 which i think is stock(??) and have had some misfire problems at high boost settings...18psi maybe. I thought it was the coils, becasue it was always on the same cyl. could it be that just those 2 cyl have a larger gap then the others?
great topic. i always was woundering this.
personally i hate gapping down. I feel its nothing more than a bandaid fix to a bigger problem.
If you cant fire off the mix with a 0.8 - 1.0mm gap, you really need to upgrade your ignition system. Gapping down does nothing more than produce a colder spark, and increase the risk of fouling plugs.
Nice hot spark makes a nice strong flame front, which makes for nice smooth even combustion. A weak spark, well ... we all know the "blown out" feeling.
Bit of a rant, i know, but i really hate gapping down - bloody tight asses, FIX THE PROBLEM, NOT THE SYMPTOM!!
Fast, Cheap, Reliable - Pick any two, and the third is laughable
Sorry, no suggestions - im not at the point of needing to fire off a mix in high boost.
Ill have to do some homework soon tho - my mates almost at the limit of his ignition system in the FC (Second gen) RX7. Afaik, he just needs better igniters to get a bit more life out of the coils.
Fast, Cheap, Reliable - Pick any two, and the third is laughable
I would like to know suggested ignition upgrades as well. Whats recommended with a Tec3r?
-Kyle 1995 Custom Turbo M3 SOLD!
so what would be the best gap for a stock motor on 8-10 psi??
With tec 22-26 will work.The tec manual gives refrence on reccomended gaps.
996WHP 2.8 and going nowhere fast
. e36 4Dr with A/C and leather seats in U.S.
www.bmwturbo328.com 9.93@152.6
where could i get a tec management?
You were right! On the dyno, I was frustrated that it was blowing out spark over about 400whp. The guy said "your exhaust vales are floating at high rpm's, you have to much backpresure"
I made my exhaust and used a $30 Summit muffler(chambered) for the midpipe. I did a pull with an open downpipe and picked up over 100whp.
The POS Summit garbage killed the power.
FWIW, I had experimented with .034-.018. The gap of .034 made great power untill about 19psi(thinking Supra land here).
The moral here is, if you think it's just ignition, it would be wise to test the air flowing in and out of the motor. Not just assume, but, test.
TEC-3R, T4 GT40, WISECO, EAGLE, SUPERTECH, O-RING'D "FRANKENSTEIN" STROKER.
996WHP 2.8 and going nowhere fast
. e36 4Dr with A/C and leather seats in U.S.
www.bmwturbo328.com 9.93@152.6
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